Menorrhagia, excessive uterine bleeding during a prolonged menstrual period, has been attributed to disorders of the endometrium. While hysterectomies provides a definitive treatment for menorrhagia, less invasive procedures are attractive as they generally entail reduced side effects, shorter hospital stays and less procedural and post-operative discomfort.
Generally, these less invasive procedures ablate tissue through the application of electrical energy (e.g., RF energy), heat (e.g., laser) or cryogenic temperatures. However, these procedures typically rely on direct visualization of the uterus by an experienced operator to ablate selected portions of the endometrium. Alternatively, the entire endometrium may be treated by conduction uterine ablation, i.e., circulating a heated fluid through the uterus. In certain of these procedures, the heated fluid may be contained within a balloon while circulating through the uterus while in others, the fluid directly contacts the endometrium. These systems generally employ a resistive element to heat the ablation fluid (e.g., saline) to a temperature within a desired range while maintaining the pressure of the circulated fluid substantially constant.